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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the currently available guideline, according to GLP and the validity criteria are considered as fulfilled.
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples were taken and analysed after 0 and 72 hours

Test solutions

Vehicle:
no
Details on test solutions:
Due to the low water solubility of the test item, the water-accommodated fraction was perapared by filtration of a saturated solution after stirring for 24 hours. Then, the test solution was disolved with the nutrient medium.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Desmodesmus subspicatus, CHODAT
Source: supplied in February 2008 by the Collection of Algal cultures, Institute of Plant Physiology, Univesity of Göttingen (Göttingen, Germany).

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
No post exposure period

Test conditions

Hardness:
Not indicated
Test temperature:
24 - 29°C
pH:
8.0 - 9.2
Dissolved oxygen:
Not indicated
Salinity:
Not indicated
Nominal and measured concentrations:
Nominal: 10, 18, 32, 56 and 100 mg/L
Measured (geometric mean): 4.42, 7.63, 11.83, 19.39 and 33.80 mg/L throughout the test.
The highest measured concentration is considered as the limit of water solubility of the product.
Details on test conditions:
TEST SYSTEM
- Test vessel: The test was conducted in round cuvettes with a diameter of 10 mm. The vessels were filled with 5 mL of the test solution.
- Initial cells density: 10exp4
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod and light intensity and quality: The cultures were illuminated constantly with a light intensity of 5800 - 6100 Lux.

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Counting chamber.
Every 24 h the cell numbers were determined for each test flask and the photometric absorption of the cuvettes were recorded. At the end of the test, the vessels were microscopically observed to verify a normal and healthy appearance of the algae.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
19 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
dissolved
Basis for effect:
growth rate
Remarks on result:
other: not applicable
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
19 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
dissolved
Basis for effect:
biomass
Remarks on result:
other: not applicable
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 34 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
dissolved
Basis for effect:
growth rate
Remarks on result:
other: not applicable
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
35 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
dissolved
Basis for effect:
biomass
Remarks on result:
other: not applicable
Details on results:
- Exponential growth in the control (for algal test): yes
Results with reference substance (positive control):
The 72 h-NOEC, the 72h- ErC50 and 72h-EbC50 of the reference substance potassium dichromate was 0.063, 1.2 and 0.31 mg/L.
Reported statistics and error estimates:
The EC50 values and NOEC after 72 hours test duration was calculated with 95% confidence limits when compared with the untreated control group.

Any other information on results incl. tables

1. 72 hour NOEC: 19 mg/L

2. ErC50: > 34 mg/L.

3. EbC50: 35 mg/L.

4. Cell deformations were not observed.

5. The growth inhibition in the treated cultures compared to the control ranged from -7.1 – 5.7 % at nominal concentrations of 10 – 56 mg/L and at nominal 100 mg/L the growth inhabitation was 34.6 %.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
1. 72 hour NOEC: 19 mg/L
2. ErC50: > 34 mg/L.
3. EbC50: 35 mg/L.
Executive summary:

The study examined the effect of Zogol 8 on green alga (Desmodesmus subspicatus) for 72 hours in a growth inhibition test. The cultures were exposed to nominal concentrations of 0, 10, 18, 32, 56 and 100 mg/L of the test substance (corresponding to measured 0, 4.4, 7.6, 11.8, 19.4 and 33.8 mg/L). The study was conducted under static conditions and in accordance with the OECD 201 guideline. The 72 hour NOEC value was determined to be 19 mg/L. The ErC50 and EbC50 was determined to be > 34 and 35 mg/L, respectively. The NOEC, ErC50 and the EbC50 values were based on cell concentration measurements. The growth inhibition in the treated cultures compared to the control ranged from -7.1 – 5.7 % at nominal concentrations of 10 – 56 mg/L and at nominal 100 mg/L the growth inhibition was 34.6 %.